Opening the floodgates: proteomics and the integrin adhesome

Cell biologists studying cell adhesion have already figured out that cell-extracellular matrix connections, mediated by integrin receptors, are diverse and extremely complex structures. Dozens of adaptors-linking integrins with the cytoskeleton, and numerous enzymes and signaling proteins-regulating adhesion site dynamics, collectively referred to as the integrin adhesome, cooperate in mediating adhesion and activating specific signaling networks. Recent proteomic studies indicate that the known adhesome complexity is just the tip of the iceberg. In each existing category of molecular function the number of candidate components more than double the known components and several new categories are suggested. Proteomic analysis of different integrin heterodimers points to integrin-specific variations in composition and analysis of adhesion complexes under varying tension regimes highlights the force-dependent recruitment of different components, most notably LIM domain proteins.